scholarly journals When True Recognition Suppresses False Recognition: Evidence from Amnesic Patients

1998 ◽  
Vol 10 (6) ◽  
pp. 668-679 ◽  
Author(s):  
Daniel L. Schacter ◽  
Mieke Verfaellie ◽  
Michael D. Anes ◽  
Carrie Racine
Keyword(s):  
Episodic Memory ◽  
Signal Detection ◽  
Study List ◽  
False Recognition ◽  
Present Experiment ◽  
Healthy Controls ◽  
Repeated Presentation ◽  
Control Subjects ◽  
Insight Into ◽  
Normal Controls

False recognition occurs when people mistakenly claim that a novel item is familiar. After studying lists of semantically related words, healthy controls show extraordinarily high levels of false recognition to nonstudied lures that are semantic associates of study list words. In previous experiments, we found that both Korsakoff and non-Korsakoff amnesic patients show reduced levels of false recognition to semantic associates, implying that the medial temporal/diencephalic structures that are damaged in amnesic patients are involved in the encoding and/or retrieval of information that underlies false recognition. These data contrast with earlier results indicating greater false recognition in Korsakoff amnesics than in control subjects. The present experiment tests the hypothesis that greater or lesser false recognition of semantic associates in amnesic patients, relative to normal controls, can be demonstrated by creating conditions that are more or less conducive to allowing true recognition to suppress false recognition. With repeated presentation and testing of lists of semantic associates, control subjects and both Korsakoff and non-Korsakoff amnesics showed increasing levels of true recognition across trials. However, control subjects exhibited decreasing levels of false recognition across trials, whereas Korsakoff amnesic patients showed increases across trials and non-Korsakoff amnesics showed a fluctuating pattern. Consideration of signal detection analyses and differences between the two types of amnesic patients provides insight into how mechanisms of veridical episodic memory can be used to suppress false recognition.

scholarly journals Effects of neuroactive metabolites of the tryptophan pathway on working memory and cortical thickness in schizophrenia

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Junchao Huang ◽  
Jinghui Tong ◽  
Ping Zhang ◽  
Yanfang Zhou ◽  
Yimin Cui ◽  
...  
Keyword(s):  
Working Memory ◽  
Cognitive Impairment ◽  
Cortical Thickness ◽  
Serum Levels ◽  
Healthy Controls ◽  
Tryptophan Pathway ◽  
Liquid Chromatography Tandem Mass ◽  
Therapeutic Development ◽  
Tryptophan Metabolites ◽  
Insight Into

AbstractA number of tryptophan metabolites known to be neuroactive have been examined for their potential associations with cognitive deficits in schizophrenia. Among these metabolites, kynurenic acid (KYNA), 5-hydroxyindole (5-HI), and quinolinic acid (QUIN) are documented in their diverse effects on α-7 nicotinic acetylcholine receptor (α7nAChR) and/or N-methyl-D-aspartate receptor (NMDAR), two of the receptor types thought to contribute to cognitive impairment in schizophrenia. In this study, serum levels of KYNA, 5-HI, and QUIN were measured in 195 patients with schizophrenia and in 70 healthy controls using liquid chromatography-tandem mass spectrometry; cognitive performance in MATRICS Consensus Cognitive Battery and cortical thickness measured by magnetic resonance imaging were obtained. Patients with schizophrenia had significantly lower serum KYNA (p < 0.001) and QUIN (p = 0.02) levels, and increased 5-HI/KYNA (p < 0.001) and QUIN/KYNA ratios (p < 0.001) compared with healthy controls. Multiple linear regression showed that working memory was positively correlated with serum 5-HI levels (t = 2.10, p = 0.04), but inversely correlated with KYNA concentrations (t = −2.01, p = 0.05) in patients. Patients with high 5-HI and low KYNA had better working memory than other subgroups (p = 0.01). Higher 5-HI levels were associated with thicker left lateral orbitofrontal cortex (t = 3.71, p = 2.94 × 10−4) in patients. The different effects of 5-HI and KYNA on working memory may appear consistent with their opposite receptor level mechanisms. Our findings appear to provide a new insight into the dynamic roles of tryptophan pathway metabolites on cognition, which may benefit novel therapeutic development that targets cognitive impairment in schizophrenia.

scholarly journals Episodic memory and speed/attention deficits are associated with Alzheimer-typical CSF abnormalities in MCI

2008 ◽  
Vol 14 (4) ◽  
pp. 582-590 ◽  
Author(s):  
ARTO NORDLUND ◽  
SINDRE ROLSTAD ◽  
OLA KLANG ◽  
KARIN LIND ◽  
MONA PEDERSEN ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Neuropsychological Battery ◽  
Prodromal Stage ◽  
Age Norms ◽  
Total Tau ◽  
Prodromal Ad ◽  
Function Language ◽  
T Tau ◽  
Normal Controls ◽  
Better Than

Mild cognitive impairment (MCI) is regarded as the prodromal stage of dementia disorders, such as Alzheimer's disease (AD).Objective: To compare the neuropsychological profiles of MCI subjects with normal concentrations of total tau (T-τ) and Aβ42 in CSF (MCI-norm) to MCI subjects with deviating concentrations of the biomarkers (MCI-dev). MCI-norm (N = 73) and MCI-dev (N = 73) subjects were compared to normal controls (N = 50) on tests of speed/attention, memory, visuospatial function, language and executive function.Results: MCI-norm performed overall better than MCI-dev, specifically on tests of speed and attention and episodic memory. When MCI-dev subjects were subclassified into those with only high T-tau (MCI-tau), only low Aβ42 (MCI-Aβ) and both high T-tau and low Aβ42 (MCI-tauAβ), MCI-tauAβ tended to perform slightly worse. MCI-tau and MCI-Aβ performed quite similarly.Conclusions: Considering the neuropsychological differences, many MCI-norm probably had more benign forms of MCI, or early non-AD forms of neurodegenerative disorders. Although most MCI-dev performed clearly worse than MCI-norm on the neuropsychological battery, some did not show any deficits when compared to age norms. A combination of CSF analyses and neuropsychology could be a step toward a more exact diagnosis of MCI as prodromal AD. (JINS, 2008, 14, 582–590.)

Creating Illusions of Past Encounter Through Brief Exposure

2009 ◽  
Vol 20 (5) ◽  
pp. 534-538 ◽  
Author(s):  
Alan S. Brown ◽  
Elizabeth J. Marsh
Keyword(s):  
Study List ◽  
False Recognition ◽  
False Belief

Titchener (1928) suggested that briefly glancing at a scene could make it appear strangely familiar when it was fully processed moments later. The closest laboratory demonstration used words as stimuli, and showed that briefly glancing at a to-be-judged word increased the subject's belief that it had been presented in an earlier study list ( Jacoby & Whitehouse, 1989 ). We evaluated whether a hasty glance could elicit a false belief in a prior encounter, from a time and place outside of the experiment. This goal precluded using word stimuli, so we had subjects evaluate unfamiliar symbols. Each symbol was preceded by a brief exposure to an identical symbol, a different symbol, or no symbol. A brief glance at an identical symbol increased attributions to preexperimental experience, relative to a glance at a different symbol or no symbol, providing a possible mechanism for common illusions of false recognition.

scholarly journals Monitoring Migraine Cycle Dynamics with an Easy-to-Use Electrophysiological Marker—A Pilot Study

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3918 ◽  
Author(s):  
Goded Shahaf ◽  
Pora Kuperman ◽  
Yuval Bloch ◽  
Shahak Yariv ◽  
Yelena Granovsky
Keyword(s):  
Pilot Study ◽  
Stress Level ◽  
Event Related Potentials ◽  
Healthy Controls ◽  
Preliminary Results ◽  
Auditory Oddball ◽  
Control Subjects ◽  
Related Potentials ◽  
Auditory Oddball Task ◽  
The Brain

Migraine attacks can cause significant discomfort and reduced functioning for days at a time, including the pre-ictal and post-ictal periods. During the inter-ictsal period, however, migraineurs seem to function normally. It is puzzling, therefore, that event-related potentials of migraine patients often differ in the asymptomatic and inter-ictal period. Part of the electrophysiological dynamics demonstrated in the migraine cycle are attention related. In this pilot study we evaluated an easy-to-use new marker, the Brain Engagement Index (BEI), for attention monitoring during the migraine cycle. We sampled 12 migraine patients for 20 days within one calendar month. Each session consisted of subjects’ reports of stress level and migraine-related symptoms, and a 5 min EEG recording, with a 2-electrode EEG device, during an auditory oddball task. The first minute of the EEG sample was analyzed. Repetitive samples were also obtained from 10 healthy controls. The brain engagement index increased significantly during the pre-ictal (p ≈ 0.001) and the ictal (p ≈ 0.020) periods compared with the inter-ictal period. No difference was observed between the pre-ictal and ictal periods. Control subjects demonstrated intermediate Brain Engagement Index values, that is, higher than inter-ictal, yet lower than pre-ictal. Our preliminary results demonstrate the potential advantage of the use of a simple EEG system for improved prediction of migraine attacks. Further study is required to evaluate the efficacy of the Brain Engagement Index in monitoring the migraine cycle and the possible effects of interventions.

scholarly journals Genotoxicity in Patients on Long-term Proton Pump Inhibitor Therapy in Korea: A Nested Case-control, Prospective, Pilot Study

2020 ◽  
Vol 20 (1) ◽  
pp. 47-53 ◽  
Author(s):  
Youn I Choi ◽  
Jun-Won Chung ◽  
Dong Kyun Park ◽  
Kyoung Oh Kim ◽  
Kwang An Kwon ◽  
...  
Keyword(s):  
Pilot Study ◽  
Medical History ◽  
Proton Pump ◽  
Serum Levels ◽  
Self Report ◽  
Healthy Controls ◽  
Control Subjects ◽  
Increased Risk ◽  
Healthy Control

Background/Aims: Although proton pump inhibitors (PPIs) remain a mainstay for the suppression of gastric acid secretion, long-term PPI use is associated with side effects. However, the genotoxicity associated with long-term PPI use is unclear.Materials and Methods: This prospective observational pilot study enrolled patients who had been on PPIs for >1 year and healthy controls from July 2015 to August 2016. The subjects completed self-report questionnaires pertaining to their drug and medical history, and only those with no medical history and a ≥2-year wash-out period (for drugs other than PPIs) were included. We collected peripheral-blood lymphocytes from long-term PPI users and healthy controls and analyzed the genotoxicity by using the cytokinesis-block micronucleus cytome assay; we also determined the fasting serum levels of pyridoxine, folate, cobalamin, and homocysteine.Results: Ten long-term PPI users and 40 healthy control subjects were enrolled. The median serum pyridoxine, folate, cobalamin, and homocysteine levels were not significantly different between the groups. The median frequencies of micronuclei (MNi), nucleoplasmic bridges (NPBs), and nuclear buds (Nbuds) per 1,000 binucleated cells, in long-term PPI users and healthy controls, were 30.3 and 16.3 (<i>P</i><0.005), 2.5 and 1.8 (<i>P</i><0.005), and 9.3 and 5.0 (<i>P</i><0.005), respectively. Even after adjustment for confounding factors, the OR of the MNi, NPBs, and Nbuds for long-term PPI users compared with healthy control subjects were 14.1 (<i>P</i><0.001), 2.0 (<i>P</i>=0.001), and 1.3 (<i>P</i>=0.3), respectively.Conclusions: Long-term PPI use was significantly associated with an increased risk of genotoxicity after adjustment for age, sex, body mass index, medical history, drug history, and the serum levels of vitamins.

scholarly journals DNA Methylation Patterns of Interferon Gamma Gene Promoter and Serum Level in Pulmonary Tuberculosis: Their Role in Prognosis

2019 ◽  
Vol 16 (1) ◽  
pp. 0178
Author(s):  
Zayr Et al.
Keyword(s):  
Dna Methylation ◽  
Immune Response ◽  
Interferon Gamma ◽  
Gene Promoter ◽  
Innate Immune ◽  
Healthy Controls ◽  
Healthy Control ◽  
Ifn Γ ◽  
Methylation Patterns ◽  
Normal Controls

Tuberculosis (TB) still remains an important medical problem due to high levels of morbidity and mortality worldwide. A series of innate immune mechanisms that create a cytokine network control the pathogenesis of tuberculosis and this response has the capacity to modify the host genomic DNA structure through epigenetic mechanisms such as DNA methylation which could constantly alter the local gene expression pattern that can modulate the metabolism of the tissues and the immune-response. Interferon-gamma (IFN-γ) is an important pro-inflammatory cytokine regulator of the innate immune response to TB. This study aims to determine DNA methylation patterns of INF-γ gene promoter and measure serum IFN- γ level in newly diagnosed TB patients, relapse TB patients, and healthy control, in order to study the possibility of using these as a biomarker for the prognosis of TB stages in patients. The current case-control study included 66 patients with TB and 33 healthy control subjects. DNA was extracted from peripheral blood(PB) of included subjects and modified using sodium bisulfate specific kit. DNA methylation patterns of IFN-γ gene promoter was determine by using methylation specific polymerase chain reaction(MS-PCR).Serum IFN-γ level  was determined using enzyme linked immune-sorbent assay(ELISA). Results showed that percentages of DNA methylation patterns in normal controls, newly diagnostic TB patients and relapse TB patients were (63.3%, 18.2% and 21.2% respectively). Also, higher significant differences (P≤0.0001) of  un-methylated  IFN-γ gene promoter patterns in newly diagnostic TB patients  than  relapse TB patients comparison with healthy controls. The percentage of un-methylated DNA patterns in healthy controls, newly diagnostic TB patients and relapse TB patients were (9.9%, 39.4% and 51.5%, respectively). The mean of serum IFN-γ levels (pg/ml) for normal controls, newly diagnostic TB patients and relapse TB patients were (59.3± 13.8,75.8±24.3 and 69.6±18.7,respectively).In conclusion, there is a relative association between methylation of IFN-γ gene promoter and predisposing to TB progression.

Visual flicker in depression: response criteria, confidence ratings and response times

1986 ◽  
Vol 16 (1) ◽  
pp. 187-197 ◽  
Author(s):  
Joseph E. Herskovic ◽  
Mitchell L. Kietzman ◽  
Samuel Sutton
Keyword(s):  
Signal Detection ◽  
Response Times ◽  
The Other ◽  
Response Criterion ◽  
Sensory Sensitivity ◽  
Major Depressive ◽  
Depressed Patients ◽  
Depressive Patients ◽  
Normal Controls ◽  
Confidence Ratings

SynopsisDifferences in response criterion and sensory sensitivity to visual flicker among major depressive patients, dysthymic patients, and normal controls were investigated. Also, signal detection confidence ratings and response times were compared. The results indicated that major depressive patients responded more conservatively (i.e. were less willing to respond ‘flicker’) than either of the other groups. The groups did not differ significantly on a criterion free measure of flicker sensitivity. The major conclusions are: (1) previously reported visual flicker differences between depressed patients and normal controls were probably due to the more conservative response criterion of the patients and not to flicker sensitivity differences between groups; and (2) confidence ratings and response times yield similar conclusions with respect to visual flicker sensitivity and response criterion. Therefore, interpretations concerning a sensory or perceptual deficit in depression must take into account the differences in response criterion between depressed patients and normal controls.

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